A skimmer is a device used to illegally collect data from credit or debit cards. It is often placed over or inside card readers at ATMs or gas pumps, capturing the information stored on the magnetic stripe of the card. This stolen data can then be used for fraudulent transactions. Skimmers can be difficult to detect, as they are designed to blend in with legitimate equipment. Some skimmers also include a small camera to capture the cardholder's PIN. Awareness of these devices is essential for consumers to protect their financial information and avoid identity theft.